If it's a hazard to a crew, it could also be a hazard to electronics that pilot the craft. If the craft comes down as a result, that could be bad news for any forests, buildings, people, etc. nearby on the ground.
There is a _significant_ difference in the damage done in a manned aircraft and unmanned aircraft. To even imply that the same laws would apply is absurd.
Of course there's a difference, but if the incident causes a fire that then spreads, that is very bad in either case. It's more likely the law exists from the fire concern than out of concern for the pilots, and the law is just waiting for an update to catch up with a world that has more drones.